High cholesterol is one of the most prevalent risk factors for heart disease—but with a healthy lifestyle, it’s also one of the most preventable. While it may seem overwhelming to try to bring down your numbers, experts say there’s one simple change that comes with a big payoff: Eating more fiber. Here’s what you need to know about the cholesterol-fiber connection and how to get more of the good stuff into your diet.
A quick primer on cholesterol
When you hear the word “cholesterol,” you probably think “bad.” But the truth is a little more complex. Cholesterol—a waxy, fat-like substance that’s found in all of your cells—is important for many of your body’s functions, such as making hormones, making vitamin D, and producing substances that help you digest food. When it comes to how much you need, though, cholesterol falls into the “Goldilocks” zone—just enough is vital, but too much leads to trouble.
“While we tend to get a lot of cholesterol from food sources, our body actually makes most of the cholesterol it needs,” says Hannah Dentry, RD, a health coach with Parsley Health. “If we have too much cholesterol in our blood, it can combine with other substances and form sticky plaques.” And if those plaques begin circulating and accumulating, it can lead to atherosclerosis (sometimes referred to as “hardening of the arteries”) and damage to the coronary arteries, which supply blood to your heart. As a result, having high levels of cholesterol can raise your risk for heart disease and stroke, two of the country’s leading causes of death.
More than 90 million U.S. adults have total cholesterol levels that are higher than what healthcare experts recommend. But total cholesterol is just part of the picture. A blood test can also measure your levels of LDL cholesterol, HDL cholesterol, and triglycerides. What’s the difference?
“One easy way to remember is to think, ‘L equals lousy and H equals healthy,’” says Dentry. “LDL carries cholesterol through the bloodstream and deposits the harmful fat into the vessel walls. HDL sponges up cholesterol from the blood vessels and moves it to the liver, where it’s deposited for disposal. It’s like the broom cleaning up the mess that the LDL has left.”
Triglycerides are another form of fat in the blood that can raise your risk for heart disease. In fact, research has found that high triglyceride levels can be an independent risk factor for cardiovascular disease regardless of your other cholesterol numbers.
How to detect and combat high cholesterol (and other biomarkers)
In addition to total cholesterol, LDL, HDL, and triglycerides, Parsley Health providers also look at a few measures of cholesterol that many doctors don’t include in labs. These give your clinician a better idea of your risk levels and where they can help you optimize your health. For instance, one measure they’ll look at is small dense LDL particles. These are denser and more atherogenic than LDL, explains Dentry. They’re also associated with a 2-3 fold increased risk of CVD. Another measure Parsley providers check is VLDL, a type of lipoprotein made in the liver that carries cholesterol and triglycerides. It’s significantly associated with elevated coronary heart disease risk, research shows.
When your provider checks your cholesterol levels, he or she may also look for related biomarkers that can indicate your risk for other cardiometabolic problems. One is a protein called apolipoprotein B, or APOB, which carries LDL throughout the body. “That biomarker gives us a really direct measure of the number of those particles that are in the bloodstream, and in some cases, can be a better indicator of cardiovascular disease risk than the LDL on its own,” says Dentry.
Another is c-reactive protein or CRP, which is made by the liver and increases when inflammation occurs in the body. “Atherosclerosis is an inflammatory process, so high CRP can be an indicator of heart attack risk,” says Dentry. “For women specifically, this test can be very accurate for predicting risk of heart disease.”
While high cholesterol can be caused by a poor diet or lack of exercise, genetics also play a major role. Hormonal imbalances can lead to higher cholesterol levels, too. “Even health conditions that seem totally unrelated, like polycystic ovarian syndrome (PCOS), can impact cholesterol,” says Dentry. “This is why it’s so important to know your numbers even if you’re young or have a relatively healthy lifestyle.”
The role of fiber and how it can help
Making changes to your diet can have a dramatic effect on your cholesterol levels. And it’s not just about cutting down dietary cholesterol, which Dentry says actually has much less of a negative impact than consuming lots of saturated fats, trans fats, sugar, and alcohol. It’s also about adding foods that can actively reduce cholesterol, and one of the most powerful is fiber.
“Fiber gets a boring rep. We think, ‘yeah yeah yeah, eat your fiber.’ But it actually has fantastic properties,” says Dentry. Fiber is part of the cell wall of plant foods, and you’ll find it in anything that grows out of the ground. It’s also completely resistant to human digestion. “If I eat oats, my body cannot use the fiber from those oats for calories, it can’t break it down for energy,” says Dentry. So what does it do instead?
Soluble fiber soaks up water in the digestive tract to form a gel, which has what Dentry calls “almost medicinal properties,” with a particularly strong effect on cholesterol. “It can bind on to the fat and cholesterol from our food and prevent some of it from entering the bloodstream,” she says. “When the bacteria in our gut consume the gel, it produces short-chain fatty acids that have been shown to lower cholesterol.”
Both soluble and insoluble fiber (which does not dissolve in water) also helps increase the liver’s production of bile acid, which is needed for removing excess cholesterol from the body. Research even shows that if you’re taking statins, a prescription drug that can reduce cholesterol levels, getting lots of soluble fiber can double the efficacy of the statins alone.
And that’s not all, says Dentry. “Foods that are high in fiber also have anti-inflammatory properties, they stabilize blood sugar, they help prevent certain types of cancer. They’re going to benefit your overall health.” A meta-analysis of nearly 250 studies published in 2019 showed that eating plenty of plant-based fiber cuts the risk of dying from heart disease by up to 30 percent, and also decreases the risk of stroke, type 2 diabetes, and colorectal cancer. We’re going to go ahead and say it: Fiber is a superfood.
How much fiber you need—and how to get it
While the USDA recommends getting 25 to 30 grams of fiber per day, Dentry says that for therapeutic effect, consider shooting for even more than that (but not more than 50 grams per day), with at least 10 grams of soluble fiber. Unfortunately, surveys show that most of us are only getting about half of what we should.
If you want to eat more fiber, Dentry suggests taking it slow. Start by tracking your current intake over three days. “If it’s an average of 12 grams, and then the next day you try to eat 30 grams, you’re going to be uncomfortable, bloated, and constipated. Instead, maybe add 5 grams a week and increase from there. And definitely hydrate really well while you’re upping your fiber.”
A health coach, like those at Parsley Health, can help you come up with a plan for slowly increasing your fiber intake and finding fiber-full foods you enjoy. You’ll find fiber in all plant-based foods, but some are particularly good sources, says Dentry. She recommends upping your intake of carrots, broccoli, onions, and artichoke, along with bananas, berries, apples, and pears. You should also try to incorporate more legumes and whole grains, like oats and barley. Chia seeds and ground flaxseeds (“they must be ground because the outer hull is too tough to penetrate and the fiber is inside,” says Dentry) also pack a huge punch of fiber in a small package—one teaspoon contains 5 grams.
At each meal, try to make half your plate non-starchy vegetables, a quarter of your plate protein, and then add half a cup of high-fiber, slow-burning starch. “If you have that composition, that’s a very high fiber plate,” says Dentry. Also, try to brainstorm ways to layer on fiber-rich foods. “For breakfast, if you’re eating a bowl of oatmeal, can you also stir in a couple of tablespoons of flax or chia seeds, and then add a bit of fruit on the side?” she suggests.
Cooking vegetables won’t reduce the fiber content, although it can make the foods more digestible for your gut. “Broccoli, for example, can be tough for people with sensitive stomachs, so cooking it can make it easier on the gut without reducing fiber content,” says Dentry. “Soaking and rinsing your beans before you cook them has the same effect.”
Juicing, however, removes pulp—and therefore fiber—from fruits and vegetables. Try making a smoothie instead, to preserve more of the fiber. Other simple swaps? Sub in quinoa for white rice, whole-wheat pasta for white pasta, sweet potatoes for white potatoes, chia seeds or flaxseeds for granola, or hummus for creamy dips.